<em>In Situ</em> Analysis of Electron-Induced Chemical Transformations in Vapor-Phase-Synthesized Al-Based Inorganic–Organic Hybrid Thin Films for EUV Resist Platform

The rapid advancement and stringent requirements of extreme ultraviolet (EUV) lithography technology necessitate the development of advanced photoresist systems for next-generation microelectronics. Recent studies have demonstrated that inorganic-based hybrid photoresists offer notable improvements in EUV sensitivity, etch resistance, and greater insusceptibility to pattern collapse compared to their purely organic counterparts. However, variations in the synthesis/coating approaches and chemistry of inorganic–organic photoresists can result in distinct exposure mechanisms. In this work, an Al-based hybrid thin film resist system synthesized via molecular (atomic) layer deposition (MLD or MALD) is explored, focusing on its electron-beam and EUV patterning mechanisms. The Al-based hybrid thin films are deposited using trimethylaluminum (TMA) and the organic precursor hydroquinone, exhibiting a saturated growth rate within the temperature range of 150–200°C. In diluted tetramethylammonium hydroxide (TMAH)-based developer solutions, the electron-irradiated Al-based hybrid thin film system behaves as a negative tone resist, achieving a sensitivity of 10.4 mC/cm² at 0.1 kV electron beam lithography (EBL). Chemical changes induced by electron exposure are also analyzed in this study using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and a unique infrared spectroscopy setup, revealing the potential cross-linking pathways. To further correlate the electron-induced chemical transformations with those mediated by EUV irradiations, a combination of X-ray photoemission electron microscopy/low-energy electron microscopy (XPEEM/LEEM) system is also employed. In conclusion, this study provides critical insights into the mechanisms underlying solubility switching and contributes to the design of advanced resist materials for EUV lithography.. Authors: Le, Dan N. [University of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000303870987); Lee, Won-Il [Stony Brook University, NY (United States)] (ORCID:0000000310439933); Hwang, Su Min [University of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000200595871); Subramanian, Ashwanth [Stony Brook University, NY (United States)] (ORCID:0000000314001533); Tiwale, Nikhil [Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)] (ORCID:0000000182297108). DOE Contract: SC0012704; SC0014664. Subjects: 36 MATERIALS SCIENCE; EUV; MALD; in situ analysis; inorganic-organic hybrid thin films; lithography; low-energy electrons; molecular atomic layer deposition; photoresist